mysql - 合并具有不同 ID 但等效数据的 MySQL 行

Question

我有一个“游戏”表，每个游戏都有不同的条目，如下所示：

gameID   internalName
1        game1
2        game 1
3        game 2
4        game2
5        game3

等等

所以，现在的问题是我想结合游戏标题（去掉空格）相同的情况。在其他情况下，gameID 为 2 的行将与 1 合并，并被删除。

此外，我想更新其他表中使用 gameID 作为外键的任何条目，以指向新键。

我知道我可以做这样的事情，以获得哪些标题有重复的列表：

SELECT gameID, count(REPLACE(internalName, ' ', '')), internalName  FROM games GROUP BY REPLACE(internalName, ' ', '') HAVING count(REPLACE(internalName, ' ', ''))  > 1

但是，这并不能真正帮助我实现我需要做的事情。

有什么帮助吗？

Answer 1

类似的东西可以帮助你开始

select g1.gameID as toKeep, g2.gameID toEliminate
from games g1
inner join games g2 on replace(g1.internalName, ' ', '') = replace(g2.internalName, ' ', '')
where g1.gameID < g2.gameID

但如果你有 3 个项目要合并，这将不会那么好......

见http://sqlfiddle.com/#!2/fb294/6

但是在存储过程或 php（或其他语言）中，您应该能够得到您想要的东西。

更好的

有了这个，即使是 3、4 或 5 个相同的结果也会起作用

select g1.gameID as toKeep, g2.gameID toEliminate
from games g1
inner join games g2 on replace(g1.internalName, ' ', '') = replace(g2.internalName, ' ', '')
where g1.gameID < g2.gameID
and g1.gameID not in (SELECT g4.gameID
                      from games g4
                      inner join games g3 on replace(g3.internalName, ' ', '') = replace(g4.internalName, ' ', '')
                      where g3.gameID < g4.gameID)

http://sqlfiddle.com/#!2/8fb21/1

编辑：（未经测试的）存储过程的示例

CREATE PROCEDURE CLEANGAMENAMES()
BEGIN
  DECLARE toKeep, toEliminate INT;
  DECLARE cur1 CURSOR FOR 
    SELECT g1.gameID AS toKeep, g2.gameID AS toEliminate
    FROM games g1
    INNER JOIN games g2 ON REPLACE(g1.internalName, ' ', '') = REPLACE(g2.internalName, ' ', '')
    WHERE g1.gameID < g2.gameID
    AND g1.gameID NOT IN (SELECT g4.gameID
                          FROM games g4
                          INNER JOIN games g3 ON REPLACE(g3.internalName, ' ', '') = REPLACE(g4.internalName, ' ', '')
                          WHERE g3.gameID < g4.gameID)

  OPEN cur1;

  read_loop: LOOP
    FETCH cur1 INTO toKeep, toEliminate;
    UPDATE <anyTable> set gameId = toKeep where gameId = toEliminate;
    -- as many tables as you need
    DELETE FROM games where gameID = toEliminate;
    UPDATE games set internalName = REPLACE(internalName, ' ', '');

  END LOOP;

  CLOSE cur1;
END;